Applicators for delivery of fluids, and in particular liquids, to the eye have been used since long for a great variety of purposes. The common eye bath for comfort, refreshment or rinsing may comprise a cup of anatomically adapted design for immersion of the eye. Delivery of large liquid amounts, usually by spray devices, has also been used in eye washes for example in emergency situations. The present invention is mainly concerned with applicators suitable for administration of relatively small amounts of fluids to the eye and also applicators of sufficient convenience in handling to facilitate or encourage frequent use, also in self-administration situations. A common application is the administration of medical to the eye. Typically the medical preparation has to be delivered in a fairly well defined volume to assure a specified dose to be delivered or absorbed. A large surplus cannot be allowed due to improper physiological effects from absorbency in non-target tissues or drainage of excess amounts through the tear channel into the throat cavity or the inconveniences caused by overflow on face and clothes. Also price considerations apply for expensive medications. As an example, the treatment of glaucoma requires frequent daily administrations of e.g. prostaglandins, beta-blockers or other expensive active ingredients, all having other then the desired pressure relieving action when absorbed by other body tissues than the eye. Moreover, proper administration of small amounts is complicated by the fact that the active ingredients cannot enter the eye but through the limited area of the cornea. Although the applicator to be described herein can be used with any fluid for any purpose, for convenience the invention will mainly be described in terms of medical applications.
The circumstances mentioned places severe demands on a applicator for the general purposes stated. The necessarily small preparation amount has to be positioned with great care in the eye not to invoke the dosing, overflow, side-effect and targeting errors mentioned. The positioning should be possible in at least one convenient patient posture for body, head and hand. Strained body positions are not only a convenience problem but may result in forced errors from stressed operation and trembling. It is desirable that the administration can be conducted in different body positions such as standing, sitting or lying, if possible also highly independent of applicator orientation. Equally important is a natural and relaxed arm and grip position during orientation, contacting and triggering. The device should also assist the user in delivering a precise volume of the preparation and not allow too small or large or inadvertently repeated ejections. Preferably a single design should fit varying anatomies without adjustments and should not induce fear for contact pain or discomfort. These requirements should be met both at patient self-treatment and operator assisted treatment. When the administration responsibility is placed on the patient simplicity is vital to suit also children, elderly and disabled persons, perhaps with reduced sight capabilities and hand strengths. On the contrary, an assistant might need to grip a device in a reverse hand position compared to the patient and may need supportive aiming means in replacement for patient tactile or visionary feedback. Finally a functional and convenient applicator device should meet several secondary demands, such as simple container refill or replacement, simple orifice opening and closure, ease of bottle identification and filling status control, open and cavity free construction for simple cleaning, overall design suitable to use and carry around in daily life and low costs for manufacture and assembly.
Prior art devices have only to a limited extent been able to fulfill the demands stated. Generally, devices for delivery of large fluid volumes are of little assistance in solving the delicate convenience, positioning and dosing problems in small volume delivery applications. As an example, the U.S. Pat. No. 1,846,763 discloses an eye bath for repeated use of an antiseptic rinsing liquid, the device having an inclination between a flask and an attached eye cup for the purpose of relieving the eye from flask weight in use but with no assisting features for any of the other purposes mentioned. In broad terms existing eye fluid applicators for small volumes are based either on drop or on spray delivery principles. Drop applicators rely on impact by gravity, typically after eye centering with an eye cup or eyelid retractor, after release e.g. by squeezing a resilient bottle. The drop method as such gives a concentrated delivery if properly positioned and is generally not experienced as uncomfortable but is not independent of applicator orientation. Common designs are not sophisticated and give little control over, and allow limited variations in, the administration sequence. Devices having parts to conform with face parts are described in U.S. Pat. Nos. 3,872,866, 4,134,403 and 4,792,334 although of unsuitable relative orientation and with no assisting hand grip part. A device example is disclosed in the patent specification EP 335,513, providing minimum support means with a hand grip type squeeze assistance but no other relief and improper orientation of the hand grip. A similar device is sold under the trademark “Opticare”. Spray applicators rely on a shower, typically released by use of a manual lever, centered on the eye with similar means as for drop applicators. The spray method as such is highly independent of applicator orientation and may give a distributed impact but is limited to very small treatment amounts before losses occur in aerosol form and the application tend to release blink reflexes. Common designs do not cope with these problems or the general demands outlined. The U.S. Pat. No. 5,201,726 discloses a device example of this kind, having extensive means for draining off non-targeted and non-condensed surplus liquid, rather than preventing its occurrence. Although provided with hand grip and trigger the device is not ergonomic for use by patient or assistant.
Accordingly there remains a need for eye fluid applicators better meeting the specific and general design demands explained.